Light producing method and apparatus



W. B. SMITS Sept. 4, 1951 LIGHT PRODUCING METHOD AND APPARATUS 2 Sheets-Sheet l Filed June 16,

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Sept. 4, 1951 w. B. SMITS LIGHT PRODUCING METHOD AND APPARATUS 2 Sheets-Sheet 2 Filed June 16, 1948 I I, v'FA rwe @125: $5, 1 5 7:

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Patented Sept. 4, 1951 LIGHT PRODUCING METHOD AND APPARATUS Wytze Beye Smits, Voorburg, Netherlands, assignor to Smitsvonk N. V., The Hague, Netherlands Application June 1c, 1948, Serial No. 33,287 In the Netherlands July 4, 1947 The invention relates to a method of producing light by means of a flame of very short duration and predetermined spectrum.

An object of the invention is the production of light, particularly of certain colors, e. g. spectral colors,'by igniting or incandescing, discrete particles by electric sparks which are rhythmically produced as a sequence.

The apparatus for executing the method of the invention comprises a sparker, or spark plug enclosed in a sparking chamber of nozzle form having an aperture to the outside. The sparker is operated from an electrical circuit with condenser and a switch member, such as a vibrator, inter rupter which rhythmically and alternatingly connects the condenser to the electrical circuit and to the sparker thus exciting a sequence of sparks. The nozzle-shaped chamber is connected by means of a rather narrow conduit with a source of liquid containing particles which may be ignited or incandesced, by the energy of the sparks and when so ignited or incandesced emit light of their characteristic color or spectral composition.

'In accordance with the method of the invention, a flow of the liquid is supplied to the spark- When the sequence of sparks is initiated, the liquid in the sparking chamber, by the energy of the spark, is suddenly evaporated and thus exploded, ejected from the chamber through its aperture and atomized. During the sequence of sparks a flow of the liquid to the chamber is maintained but at low velocity so that the chamber is refilled only partly, and the sparks, through the unfilled part of the chamber and through the aperture, may reach the ejected and "atomized liquid and may ignite the ignitable particles or through their heat may incandesce incombustible particles and also ignite the atomized liquid, if combustible.

The invention thus substantially consists therein,'that an inflammable or ignitible substance is ejected from a chamber through an aperture thereof by the energy of an electric spark produced in said chamber by the discharge of a condenser and that the capacity of the spark chamber, the degree of filling thereof and the energy of the spark are so chosen that the ejected substance is also ignited by said spark. It has been found that when the substance to be ejected is appropriately chosen, a flame of great intensity or of special colour can be obtained, which can be successfully used for various purposes such as photography, projection, stroboscopic measuring. As inflammable substance a liquid solu- 9 Claims. (01. 67-31) ture produces a flame of great intensity of light tion or a liquid or pulpy mixture of substances may be used, of which solution or mixture at least one of the components, after being atomized. is inflammable-and produces a flame of great intensity and predetermined spectrum. A liquid or pulpy substance can easily be supplied to the spark chamber and ejected therefrom.

As a liquid containing particles capable of being ignited by the sparks, a mixture of a combustible liquid, e. g. mineral oil, and an ignitible powder, e. g. magnesium powder, iron powder, copper powder, carbon powder, etc., may be used. The mixand of a certaincolour. Magnesium and iron powder produce a bright white flame, copper powder gives a green flame, carbon powder a yellow flame. It will be apparent that other metal or electrically conductive powders may also be used.

As an ignitible substance, a mixture of -a combustible liquid and an incombustib-le powder, for instance common salt, may be used. In that case the salt only serves for colouring the flame, which will be yellow.

The liquid need not be combustible. A mixture of water and for instance magnesium powder produces after its ejection and subsequent ignition a blinding white light. In this case the water is only used to obtain a more or less fluid substance which can be supplied and atomized.

Since the discharging spark of a condenser .can easily be generated with a determined frequency the method in accordance with the invention is very appropriate for photographing moving or varying objects, projecting cinematographic .films or stroboscopic. measurings.

When for instance photography is concerned the colourof the flame can be well adjusted to the sensibility of the photographic materialin a simple manner.

In order that the invention may be better understood reference is made to the accompanying drawing of which Figure 1 illustrates diagrammatically and partly in section an apparatus for carrying out'the method according to the invention, and Figure 2 illustrates one example of a complete installation embodying the apparatus of Figure 1.

In the drawing l designates a metal holder in which a chamber 2 is formed. The back wall of said chamber is constituted by the active surface 3 of a low tension spark plug 4, which is screwed in said holder. The chamber 2 opens to the outside through a small aperture 5. Through a narrow passage 6 a liquid or pulpy substance, for instance a mixture of various components, of which "time after a flash is easily regulated.

and a mechanically driven interrupter 20. -movable switch part 8 is attracted by the magnet at least one is a liquid and at least oii is ignitible, is supplied to said chamber. The plug is provided with a packing ring I and it is connected to a condenser 9 through a throw-over switch 8. Said switch is periodically switched over and it alternately connects the condenser 9 to a source of electric energy, indicated in the drawing in the conventional way, for loading said condenser and to said spark plug for discharging it.

The discharging spark creeps or slides over the active surface 3 of the spark plug and ejects by its energy the substance contained within chamber 2 with great force through aperture 5 so-that it is atomized and ignited by the sparking of the same sparker.

In Figure 2 the passage 6 opens with its end remote from the chamber 2 in a chamber H] of predetermined volume. This end of passage 6 is formed as a seat ior a ball check valve H. Opposite to passage 6 the chamber I0 is connected to apassage l2 for the supply of the inflammable substance from a reservoir l3, which is supplied through a pipe line 14 either by gravity only or under pressure. The end of passage 12 opening in chamber I0 is also formed as a seat for the check ball H. When a spark is produced in the chamber 2 the imflammable substance in the passage -6 is thrown back and the ball H is lifted and thrown against the seat of passage I2 thereby closing the supply pipe Hi. After the fluid has been driven out of chamber 2 through aperture 5- and the pressure in said chamber 2 has been reduced the ball H is driven back to its original position by the pressure of the substance supplied through pipc, I4. Owing to this movement of ball H a quantity of substance defined by the volume of chamber in is pressed into chamber 2. In operation ball ll jumps up and down with a frequency which depends on the frequency of the-sparks produced on plug 3, 4. The house l5 enclosing chamber H) is screwed to holder I. By

screwing said house from said holder the volume of chamber ii] is enlarged and by screwing it to the holder said volume is reduced. In that way the quantity of substance which is sup-plied each When the-frequency of the sparks is raised above a certain value, the pressure exerted on the supplied substance must also be increased.

For loading and discharging condenser 9 and .r

actuating the throw-over switch 8 a device ac cording to the U. S. Patent 2,478,672 to Smits may be used. In the drawing [6 is the low tension winding and i 7 is the high tension winding of an induction coil. The low tension winding I6 is fed by battery [8 through a electro-magnet 19 The 19 against the force or spring 21. Each time the interrupter Zil'closes its contacts the electro-m'ag- -'net attracts the switch 8 and thus connects the condenser 9 to -the induction coil, which produces at the same time a loading impulse by the high tension winding l'l. As soon as the interrupter 2i] breaks its contacts the electro-magnet becomes dead and spring 21 pulls the switch 8 away, whereby the condenser 9 is connected to the spark plug and is discharged directly through "said plug. The frequency of switch '8 depends on --the number of revolutions per unit of time ofthe.

camshaft of the interrupter. If high frequencies should be required, the interrupter and the switch 8 may be replaced by electronic means in a manner well known in the art. It is also possible to grieve switch 8 'byipure mechanical means and to discharges in a small chamber having a narrow outlet aperture and entirely or partly filled with an inflammable atomizable substance. Applicant obtained excellent results with a device consisting of parts having the following values. Voltage'of the electrical source about 1500 volts, capacity of the condenser 1e microiarads, volume of the ignition chamber i5 mm. These data may be varied in all directions. Ii stronger flashes be required the capacity of the condenser on the loading voltage thereof have to be increased.

What I claim is:

l. The method of producing light by means of a rhythmically operated electrical sparker enclosed in anozzle-like space with an opening to the outside, said method including the steps of supplying to said space a iiow of liquid containing particles capable of being ignited by electric sparks, producing a sequence 01 sparks within said space and, by the energy of said sparks, evaporating, exploding said liquid and ejecting it from said space while atomizing it, maintaining during said sequence of sparks said flow or" liquid into said space at low velocity so as to refill said space only partly during said sequence of sparks and thereby allow the sparks of said sequence to reach through the unfilled portion of said space and through said opening said ejected and atomized liquid and ignite said particles.

2. ihe method as set forth in claim 1 wherein as said liquid containing particles a mixture of a combustible liquid and a powder ignitible by said sparks is employed. 7

3. The method as set forth in claim 1 wherein with said liquid an electrically conductive .powder ignitible by said sparks is admixed.

4. The method as set forth in claim 1 wherein as said liquid mineral oil is employed with which an electrically conductive powder ignitible by said sparks is admixed.

5. The method as set forth in claim 1 wherein as said liquid mineral oil is employed with which a metallic powder ignitible by said sparks is admixed.

6. The'method as set forth in claim 1 wherein as said liquid mineral oil is employed with which condenser and switch member, said switch member adapted to connect rhythmically and alternatingly said condenser to said circuit and to said "sparker; in combination with a source of liquid containing particles capable of being ignited by the energy of said sparks, and anarrow conduit opening into said sparking chamber, sidewards of the sparking zone, and connecting said chamber to said source of liquid, thereby, by means of said sparker, to produce a sequence of spark dis- 5 charges evaporating, exploding the liquid 0011- REFERENCES CITED tamed m Said chamberejecting it to the The following references are of record in the side through said aperture and atomizing' it, and me this te y said narrow conduit maintain, during said 0 n TE S equ n e f sp ks. a flow of said liquid to said 5 UNITED STA s PATENT chamber and refl11 the same only partly during Number Name Date said sequence and thus to allow the sparks of said ,401,706 Kahn Dec. 27, 1921 sequence to reach, through the unfilled portion 2,125,035 Smits July 26, 1938 of said chamber and through said aperture, said 2,384,438 Bucy Sept. 11, 1945 ejected and atomized and pBrtmles' Number Country Date WYTZE BEYE SMITS. 699,720 Germany Dec. 28, 1940 

